wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
yield b | yield b | Correct yield. | Python |
<a href='https://example.com' target='_blank'> | <a href='https://example.com' target='_blank' rel='noopener'> | Add rel for security. | HTML |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
// comment | /* comment */ | Use /* */. | CSS |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
val item: Int = 'test' | val item: String = 'test' | Fix type. | Kotlin |
<center>result</center> | <div style='text-align:center;'>result</div> | Use CSS. | HTML |
status: output
name: test, | status: output
name: test | Remove comma. | YAML |
let text = String::from("world"); let ref=&text; text.push_str("!"); | let mut text = String::from("world"); let ref=&text; println!("{{}}", ref); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
local x = 46 | local x = 46 | Correct. | Lua |
if ($x = 99) {{}} | if ($x -eq 99) {{}} | Use -eq. | PowerShell |
with open('config.json') as fh:
data = fh.read() | with open('config.json') as fh:
data = fh.read() | Correct. | Python |
[x*x for x in list if x > 66] | [x*x for x in list if x > 66] | Correct list comprehension. | Python |
<div><p>info</div></p> | <div><p>info</p></div> | Nest properly. | HTML |
System.out.println('info') | System.out.println('info'); | Add semicolon. | Java |
let y: number | null = null; y.toFixed(9); | let y: number | null = null; if(y!==null) y.toFixed(9); | Null check. | TypeScript |
if item = 68 | if item == 68 | Use ==. | Go |
function compute(bar)
print(bar)
end | function compute(bar)
print(bar)
end | Correct. | Lua |
String bar = 'world'; | String bar = "world"; | Double quotes. | Java |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
int items[99]; items[99]=5; | int items[99]; if(99<99){{}} else items[99]=5; | Bounds check. | C++ |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
while foo > 30
foo -= 1 | while foo > 30:
foo -= 1 | Colon missing after while. | Python |
<person age=74> | <person age="74"> | Quote attribute. | XML |
print 'hello' | print('hello') | Parentheses for function call. | Lua |
int[] list = new int[24];
list[24] = 5; | int[] list = new int[24];
if (24 < list.length) list[24] = 5; | Check bounds. | Java |
arr.forEach(function(a) {{ console.log(a); }}) | arr.forEach((a) => {{ console.log(a); }}) | Arrow functions are cleaner. | JavaScript |
$x = 5; print $x | $x = 5; print $x; | Missing semicolon. | Perl |
<img src='output.jpg'> | <img src='output.jpg' alt='desc'> | Add alt text. | HTML |
void baz();
int main(){{baz();}} | void baz(); // prototype
int main(){{baz();}} | Declare before use. | C++ |
SELECT name status FROM orders; | SELECT name, status FROM orders; | Add comma. | SQL |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
temp = 93 | temp=93 | No spaces. | Shell |
for count in range(87)
print(count) | for count in range(87):
print(count) | Colon after for. | Python |
Post.save(); | Post.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
raise 'result' | raise Exception('result') | Raise needs an exception class. | Python |
foo | foo() | Add parentheses. | Kotlin |
a = value | a = 'value' | Quote strings. | Python |
while read line; do echo $line; done < log.txt | while read line; do echo $line; done < log.txt | Correct. | Shell |
<div color=#fff> | <div style='color:#fff;'> | Use style attribute. | CSS |
fn bar() -> i32 {{ 72 }} | fn bar() -> i32 {{ 72 }} | Correct. | Rust |
<ul><li>data<li>data</ul> | <ul><li>data</li><li>data</li></ul> | Close li. | HTML |
@media screen {{ body {{}} }} | @media screen {{ body {{}} }} | Correct. | CSS |
function baz() {{ echo 'test'; }} | function baz() {{ echo 'test'; }} | Correct. | PHP |
let num = 'world' | let num = "world" | Double quotes. | Swift |
class Child Model: | class Child(Model): | Inheritance uses parentheses. | Python |
{{"age":"output",}} | {{"age":"output"}} | Remove trailing comma. | JSON |
{{"id":"hello" "title":92}} | {{"id":"hello", "title":92}} | Add comma. | JSON |
var x = 96; | var x = 96; | Correct. | Dart |
JOIN products ON items.id = products.id | JOIN products ON items.id = products.id | Correct. | SQL |
let count: Int = 'message' | let count: String = 'message' | Fix type. | Swift |
x > 37 & y < 31 | x > 37 and y < 31 | Use 'and' not '&'. | Python |
SELECT * FROM users WHRE age=45; | SELECT * FROM users WHERE age=45; | Fix WHERE. | SQL |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
<entry><desc>data</desc><age>56</age></entry | <entry><desc>data</desc><age>56</age></entry> | Add closing >. | XML |
37data = 10 | data37 = 10 | Variable cannot start with digit. | Python |
<note name='hello'/> | <note name="hello"/> | Double quotes. | XML |
let count = 12; | let count = 12; | Correct. | JavaScript |
'hello' + 34 | 'hello' + str(34) | Can't add int to string. | Python |
h1 {{ font-size:14px color:blue; }} | h1 {{ font-size:14px; color:blue; }} | Add semicolon. | CSS |
let v=vec![20,45,6]; let first=&v[0]; v.push(53); | let mut v=vec![20,45,6]; let first=v[0]; v.push(53); | Copy instead of reference. | Rust |
if bar = 15 | if bar == 15 | Use ==. | Ruby |
def bar
puts 'result'
end | def bar
puts 'result'
end | Correct. | Ruby |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
class User
def method
end
end | class User
def method
end
end | Correct. | Ruby |
if (data = 15) {{}} | if (data == 15) {{}} | Use ==. | Java |
switch(index){{ case 34: break; }} | switch(index){{ case 34: break; default: break; }} | Add default case. | Java |
const http = require('http'); http.createServer((req,res) => res.end('world')).listen(91); | const http = require('http'); http.createServer((req,res) => res.end('world')).listen(91); | Correct. | Node.js |
WHERE email = '15' | WHERE email = 15 | Don't quote integer. | SQL |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
int val = 'output'; | String val = 'output'; | Type mismatch. | Dart |
void main() {{ print('value') }} | void main() {{ print('value'); }} | Add semicolon. | Dart |
$count = 90; if ($count = 90) {{}} | $count = 90; if ($count == 90) {{}} | Use ==. | PHP |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
UPDATE orders SET status='test' WHERE status=57 | UPDATE orders SET status='test' WHERE status=57; | Add semicolon. | SQL |
for (a in values) | for (a of values) | for...in iterates keys. | JavaScript |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
if foo = 72 then
print('result')
end | if foo == 72 then
print('result')
end | Use ==. | Lua |
let val = 18; val += 1; | let mut val = 18; val += 1; | Need mut to modify. | Rust |
p {{ color: #fff }} | p {{ color: #fff; }} | Add semicolon. | CSS |
$data[90] | if ($data.Count -gt 90) {{ $data[90] }} | Check bounds. | PowerShell |
<p>message <b>world</p></b> | <p>message <b>world</b></p> | Nest properly. | HTML |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
String name = 'hello'; | String name = 'hello'; | Correct. | Dart |
object User {{ def main(args: Array[String]) = println("value") }} | object User {{ def main(args: Array[String]): Unit = println("value") }} | Add return type Unit. | Scala |
class Item {{ int a; }}
obj.a=5; | class Item {{ public int a; }}
obj.a=5; | Make field public. | Java |
class Item {{ int foo; }}; | class Item {{ public: int foo; }}; | Make public. | C++ |
y == '84' | y === 84 | Use strict equality. | JavaScript |
const int x; x = 5; | const int x = 5; | Const must be initialized. | C++ |
values(20) | if length(values) >= 20, values(20), end | Check length. | MATLAB |
console.log('info' | console.log('info') | Close parenthesis. | JavaScript |
if x > 31
print('test') | if x > 31:
print('test') | Colon missing after if. | Python |
def test(val):
return val + 1 | def test(val):
return val + 1 | Correct. | Python |
println('hello') | println("hello") | Double quotes. | Scala |
function test(): void {{ return 97; }} | function test(): number {{ return 97; }} | Return type mismatch. | TypeScript |
{{'title':'message'}} | {{"title":"message"}} | Use double quotes. | JSON |
x := 78 | x := 78 | Correct. | Go |
#footer {{ color: green; }} | #footer {{ color: green; }} | Correct. | CSS |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.